Expecto Patronum
by thisisforyou
Summary: An unexpected study arrangement between John and Sherlock, new Auror trainees facing their first big exam, brings into sharp relief things which John had been trying rather hard to keep hidden. Because I couldn't just write Potterlock, oh, no. I had to throw some Uni!lock and sex and far too many canon Next Gen Potter references in there as well.


**A/N: This exists because of the encouragement of chocolate fish, who is still one of my dearest friends. When I decided I wanted to write some PotterLock I sat down and devised an entire universe, and this is only the tiniest sliver of that. I'll probably write more. Especially if coerced.**

* * *

James Potter awoke with a dazed expression, as though surprised to find himself flat on his back on the living-room floor with his best friend looming over him. He blinked, twice, and then accepted the hand that was offered to him and hauled himself back to his feet.

"Well, you've definitely got the hang of that advanced defence," he said, rubbing the small of his back where the precautionary cushions had failed to protect him. "I think that's enough practice."

John laughed. "_You_ were the one who suggested I practise them on you," he reminded him. "I told you, the practical spells aren't what I'm having problems with. There's just so much _theory_."

"Yeah, Godric forbid you actually have to _work _to be an Auror_,_" James drawled, limping theatrically to the kitchen and tapping the kettle with his wand.

The kitchen table was completely hidden under textbooks and endless scrolls of parchment. John threw himself back into a chair and immediately felt his brain cloud over. "It seems so pointless. Who cares who _invented_ the Incolumus Charm so long as we can cast it properly?"

James hefted himself up onto the kitchen bench, ignoring John's frown. "Actually, that one's easy. Aunt Hermione invented it."

John rolled his eyes. "Thanks," he said dryly, pulling the relevant piece of paper in front of him. "This has got to be so much easier for you. You're related to half the people that founded the Post-War Defence movement."

The Chaser shrugged unconcernedly. "Much to my embarrassment," he lamented, pushing gracefully off the bench and collecting a travel-mug of tea.

"And theirs," John commented idly. James smacked him lightly on the head on the way past. "I'll pass on the tea, thanks for asking."

"That's what I thought," his friend retorted. "I'll leave you to your books, I'm off to Alice's for the night."

John waved him off, secretly pleased. James meant well, but it was incredibly difficult to memorise names and dates and the history of the Second Wizarding War with the eldest Potter bouncing around with his usual manic energy in the background. Especially because James just _knew_ this stuff. John hated to think how far behind he'd be if he hadn't been in and out of the Potter household growing up.

The front door of the flat banged closed with a shouted _ciao!_ from James. John closed his eyes, trying to clear his mind and focus on his study, until he felt himself starting to drift off to sleep and cursed to himself. Living with James had its ups and downs: playing Gobstones until one in the morning was not a particularly tactical move in the week leading up to an exam.

_Until the end of the Second Wizarding War the three Unforgivable Curses had no defence, _he read for the thousandth time. _However, they were so frequently and so effectively used by the Death Eaters in the war that considerable effort was made by independent defence groups after the fall of the Ministry to develop a counter-curse. A breakthrough was made in 2005 by Hermione Granger in the shape of the Incolumus Charm. The charm is designed to –_

John growled in frustration as someone knocked on the flat's front door. Most of the people in the building knew that he had an exam the following afternoon, and most of them wouldn't dare to disturb him after the time he'd put a Stinging Hex on the door-knocker before his Healing finals.

_Probably James forgot his keys_, he reasoned to himself, yanking the door open violently. "What'd you forget?" he asked the knocker before the door was fully open.

The curly-haired teen outside widened his eyes innocently. "I'm sorry?" he said politely.

John stared at him. "Sherlock," he said, allowing the surprise to show in his voice. "Sorry, I thought you were my flatmate."

Sherlock Holmes smiled hesitantly and held out a box of dark Chocolate Cauldrons with mint fillings. "I brought sustenance. Can I come in, please?"

For a moment, John thought about protesting that he couldn't just be bought off with chocolate, but the dark mint Cauldrons were his favourite, so he threw the door open and watched his younger classmate glance nervously around his living room. "What are you doing here, Sherlock?" he asked, closing the door behind him. "Are you all right?"

He'd been surprised to see the young Slytherin on his first day in Auror training. He hadn't known him very well at Hogwarts, but he had kept very carefully to himself. John had occasionally heard the teachers complaining about how someone so apparently unconcerned about class could get such good grades, and he'd automatically assumed that the boy would go into a more academic, solitary career. But because John was three years older than most of the rest of the yeargroup, and Sherlock didn't seem to have taken any of his school-friends into training with him, they had been pushed together fairly frequently when they needed partners for practical work. John had been surprised at how easy the dark-haired teen had been to talk to once he made the attempt, and in the six months they had been training together he'd come to rather like his dry, intelligent sense of humour and the idle observations he made about the people around him.

That didn't explain what he was doing in John's house. Sherlock was always the first one out of the Ministry at the end of the day, and even though John had tried to invite him to various study groups or Leaky Cauldron quiz nights he had always refused. Now, though, he had put the box of confectionary down on top of the Post-War Defence textbook and was fidgeting restlessly with his hands.

"I'm… having trouble with some of the spells for the test," he said finally, his eyes firmly on his shoes. "I thought… well, I've seen you do all of the spells, but the theory doesn't come easily to you. I understand all of the theory, but I need help with the spells. I thought we could help each other."

John stared at him. He'd _thought_ that the younger boy was struggling with some of the practical work, but Sherlock hadn't commented so he'd ignored it out of respect for his pride. Sherlock was the smartest person John had ever met and he knew it. He recognised how much courage it would have taken to admit his weakness to anyone.

"All right," he said cheerfully. "The kettle's just boiled, do you want tea?"

Sherlock smiled weakly. "White and one sugar, please." He sat down in the chair John had vacated to get the door and thumbed absently through his study notes. John watched him as he brought the kettle back onto the boil with a tap of his wand and spooned tea leaves into two mugs.

He remembered Sherlock at Hogwarts. He'd been a strange kid, hunched into his Slytherin robes and avoiding the company of almost everyone. He was from a pure-blood family, and there were rumours that his parents were in Azkaban for supporting Voldemort in the war. John knew this couldn't be true – the last Death Eater arrest had come before Sherlock was born and it wasn't like they were rounding up everyone who'd thought he was even a little bit right – but he'd understood why people thought so. Hardly anyone was sorted into Slytherin, and those that were made a point of sticking together so as not to be bullied, and so Sherlock on his own seemed to _invite_ trouble. John remembered very clearly pulling a couple of burly second-year Gryfindors off him two weeks into his first year as a Prefect. When he'd asked Sherlock if he was all right the boy had shrugged his hand away and stalked off.

"So," he said briskly, handing Sherlock his mug and sliding into a chair beside him. "What particular spells were you having trouble with?"

Sherlock had grown up a lot since John had left school, and he'd be lying if he said he hadn't noticed. The gangly thirteen-year-old had broadened into a confident and talented young wizard, and John had caught himself more than once admiring the way his chest had filled out into robes that actually fit, until he'd finally admitted to himself that he was a little bit besotted. Which probably wasn't healthy, considering he'd never seen Sherlock look at _anyone_ with anything resembling interest. Now, though, he was grimacing and fiddling with the edge of the nearest piece of parchment, looking hugely self-conscious and so _vulnerable_ that John's stomach was twisting itself into sympathetic knots. "I… I can't get a lot of the Active Defence spells to work. My Shield Charms and things are fine, but I still can't make a corporeal Patronus and I don't understand what I'm doing wrong."

John nodded sympathetically. "You know, a lot of fully-qualified wizards can't produce a proper Patronus. It is _hard_ magic."

"Not a lot of _Aurors_, though," Sherlock retorted. "The Patronus Charm is worth ten percent of the exam."

He looked so wound up that John bit back a chuckle and took a pacifying sip of tea. "I'm not saying you don't need to be able to do it, I'm just saying it's hard, and you shouldn't feel bad about having trouble," he said calmly. "Take a deep breath, first of all, you won't be able to do it if you're panicking about how important it is. Why don't you help me with theory first? You're good at theory, and the Patronus Charm will be easier when you're a bit more comfortable."

Sherlock swirled his teacup between his hands until his frown smoothed out slightly. "All right," he said finally. "Where do you want to start?"

"I'm just having trouble with memorising names and dates," John admitted, pushing a few pieces of parchment aside. "I don't understand how you can just _learn_ them."

The younger boy shrugged self-deprecatingly. "I have a highly organised mind," he said matter-of-factly. "I've trained myself to encode things in a specific way and I delete irrelevant information."

John raised an eyebrow incredulously. "You just _delete_ it? Just like that?"

Sherlock made an impatient noise. "You've heard of a Penseive, right? Well, if you can take thoughts and memories from your mind and put them in a Pensieve, or bottle them and give them to someone else, why can't you just throw them away?" He lifted his wand – thin and dark and elegant-looking – to his temple and withdrew a tiny gossamer thread of thought, letting it hang between them for a moment before casually dropping it into the saucer of his teacup. John leaned over in time to see the noticeboard in the lobby swim around the surface before fading away. "Like that."

"That's amazing," John said, staring at the thought. Sherlock shifted self-consciously, his mouth twitching into a hesitant smile. "Just think, you could read your favourite book for the first time as often as you liked."

The former Slytherin looked at him as though this was the most ridiculous idea he had ever heard. "What?"

John grinned at him. "You could discover something wonderful over and over again. Haven't you ever wished you could recreate something like that?"

Apparently not; Sherlock stared as though John had grown antlers and then looked back at the parchment in front of him. "Is there anything you don't _understand_? Or is it just memorising things you're having problems with?"

"The Incolumus Charm," John supplied immediately, smiling at the abrupt change of subject. "I understand what it does and how to cast it, but I can't see _why_ it works."

Sherlock gave him the ghost of a smile. "Of course – they added the Incolumus Charm to the NEWT syllabus in my fifth year, so you wouldn't have studied it. This is probably the one place your age puts you at a disadvantage."

John shrugged, taking another sip of tea. "Also, you've just come straight from your DADA NEWT. All your defensive magic is still in your head. I'd forgotten everything I knew about everything not related to Healing, I had to learn it all over again."

The younger boy shifted in his chair, peering at John over the edge of his teacup. John's heart picked up at the look; Sherlock was regarding him as though he was the most interesting thing in the entire universe. He'd been on the receiving end of that look before: he wondered if that was the moment he'd first realised that he might be in trouble with his feelings for his yearmate. "Why _did_ you drop Healing?" he asked after a moment. "You'd finished the course, they offered you a position at St Mungo's – half the people in your course would have killed to be where you were. And then you gave it up and started training for a completely different career."

He smiled. "I suppose I thought… St Mungo's aren't the only people who need trained Healers. And even though I didn't officially get the title when I came here, I'd still be able to use the training to help people." Sherlock's face was inscrutable; John tipped his head to one side to attempt to decipher what he thought of the information. He wasn't sure why it was so important that the younger student approved of his choices, but suddenly it really _was_. "And you? I didn't know you well at Hogwarts, but I was surprised to see you at the beginning of the year."

Sherlock's face twisted suddenly into a smile. "I didn't want to do what people expected," he said, shrugging. "Although, I think half the people in my year _expected_ I'd run away and form some kind of Neo-Death Eater group. Being an Auror seems… it's interesting, and challenging, and you always know when you've done well. There are so many things to think about that it consumes your mind, you can only think about the job that you're doing. I thought about a lot of careers, but an Auror was the only one where I could picture that happening."

John supposed that a lot of his reasons were similar. An Auror just seemed to have a far more _exciting_ job than a Healer, and if there was one thing he didn't want to be, it was bored. He lifted his teacup in a salute. "To the avoidance of ennui," he toasted.

The former Slytherin grinned and lifted his own mug to return the gesture. "Have a Cauldron," he suggested, nudging the box towards John.

He couldn't resist them, and from the way Sherlock smiled when he opened the packet, he guessed that the younger student knew it. "How did you know they were my favourite?"

Sherlock shrugged, not quite meeting his eyes. "I've seen you eating them a few times."

"What, and you didn't delete the information?" John teased.

Sherlock's abnormally sharp cheekbones actually turned a delightful shade of pink. "It was relevant," he excused. "Would you have let me in if I didn't have them?"

Bemused by the younger boy's embarrassment, John didn't push the subject. Sherlock had already opened up more than he'd ever done before; if he got too embarrassed he might just clam up for the rest of the evening. "Of course I would have," he dismissed, but he bit into the Cauldron anyway. "I wasn't about to just leave you on my doorstep."

He tipped the open end of the box towards Sherlock, and the curly-haired youth reached in and took a Cauldron. For a few moments they munched in surprisingly easy silence. It had struck John from the first time they had worked together in practical training how neatly the two of them seemed to fit together, how comfortable he was merely being silent with the other boy in a way he barely was with his oldest friends. "Right," Sherlock said finally. There was a tiny smear of dark chocolate at the corner of his full lips; John contemplated reaching out and wiping it away before sense kicked in and he forced himself to sit up and pay attention to what he was _saying_ instead. "The Incolumus Charm."

"It was invented by Hermione Granger in 2005," John said proudly. "I know that because she's married to my flatmate's uncle."

Sherlock smiled fondly. "Yes, that's very good, John," he said, purposefully patronising, the sort of tone one might use on a child. John laughed. "The Incolumus Charm is designed to counteract the Unforgivable Curses. How much do you know about those?"

"I've never cast one, if that's what you mean," John deadpanned. Sherlock's face twisted into a mask of horror before John laughed and he relaxed, looking embarrassed again. "I know a bit. I understand them, I think."

Sherlock nodded briskly. "Right. Well, the Unforgivable Curses are a matter of willpower, of _wanting_ it to happen. You could make the right movement and say the right words right now, John, but I wouldn't feel anything from your Cruciatus Curse because you don't really want to hurt me." He considered this for a moment. "Yet," he corrected. "You might, later this evening. Depending on how this study goes."

John laughed incredulously. "I could never want to hurt you," he assured the younger boy.

"No? Give it a bit longer," Sherlock said dryly. "Anyway, the _will_ is the important part of the Unforgivables. So the Incolumus Charm is designed to cloak the caster's mind, if you like, so that the Unforgivable Curse has no target and it just dissipates. It takes a huge amount of concentration to hold the charm for any length of time."

"Yes, I know," John commented, reaching for the box of Cauldrons. Sherlock raised an eyebrow.

They settled into an easy rhythm; once John was able to explain the reasoning behind the Incolumus Charm on his own Sherlock started testing his knowledge of names and dates and the theory behind the other areas of defensive magic in the exam. The Slytherin colour-coded his notes with a few taps of his long wand and created strings of ticker-tape-like timelines of dates and charms until John's head was spinning but he could answer every question that Sherlock fired at him, sometimes literally, flicking luminescent dates out of the end of his wand or laughing as smoky incantations dissipated in John's face. Eventually the boy sat back in his chair and bit into another Chocolate Cauldron. "Good," he said through a mouthful of mint and chocolate. "Take a break. We'll come back to it later and see how much of it actually went into your long-term memory."

John smirked at the implication that not much of it had. He certainly felt a lot more confident, though Sherlock had explained his theory that he could answer the questions because the information was already in the front of his mind. He wasn't sure he believed all the things that his classmate had claimed to know about the mind, especially after he'd mentioned that the theories came from Muggles. "Okay," he countered quickly. "Patronus time."

Sherlock's smile disappeared as though John's words had Vanished it. "All right."

"Finish your Cauldron," John insisted. "Then… why don't you show me what you're doing now, and maybe there'll be something obvious that you're doing wrong."

They finished the rest of the packet of Cauldrons and another cup of tea each before Sherlock finally got up and held his wand at the ready. John smiled fondly at the expression of desperate concentration on his face. The thought briefly crossed John's mind that he'd like to hold him close and kiss him until he calmed down before he pushed it violently away. From the throwaway comments Sherlock had given him throughout their association it sounded as though he was the first friend the younger student had tried to make in a very long time. He couldn't ruin that friendship, especially not so soon after Sherlock had admitted it existed. He watched instead as Sherlock brandished his wand and cried, _"Expecto Patronum!"_

His wand movements and pronunciation were positively textbook, but not even the tiniest wisp of silvery vapour emerged from the tip of his dark wand. John frowned. Sherlock's cheeks pinked. "Sometimes I get a sort of smoke," he excused.

John nodded. "Well, your wandwork is beautiful," he complimented. Sherlock had a natural grace that John envied, and the swift movements of his wrist looked effortless and elegant in a way that John's never did. Faced with the praise, the former Slytherin flushed harder. "What's your… what do you think about when you cast?"

Sherlock frowned. "How do you mean?"

"Well…" John blew air out of his cheeks, trying to find the right way to phrase his explanation. "Okay, I learned how to cast a Patronus from Harry Potter, and the way he taught me is different from the way they taught in Auror training. He learned how to cast them as a defence against Dementors so the way he taught me to think about them is different because Dementors aren't so common anymore – a Dementor feeds on happiness, right?" Sherlock had sat back down and raised an eyebrow coolly at him. "Well, a Patronus is _made_ of happiness, and that's how it defends you against them. They feed on that instead of you. So, I think your problem is that you're not putting enough happiness behind the spell. Mr Potter said he does it with a happy memory, you know, remembers something that made him really happy and uses that to conjure his Patronus. So maybe try to remember the happiest moment of your life, and use that energy to cast the spell."

The younger student stared at him for a moment. "The happiest moment of my life," he repeated softly.

John let him think. The memory hadn't come to him quickly, either – he'd moved through getting his Hogwarts letter and his first girlfriend and a whole number of other happy moments before deciding on the moment that had set his friendship with James in motion. After a while, he'd dropped the memory entirely and just used the _feeling_ of being completely happy to generate the Patronus. After a few moments, Sherlock stood up again, gave John a quick, nervous glance, then closed his eyes.

"_Expecto Patronum!"_

This time a thin, smoky trail of something trickled out of the end of his wand and hovered between the two trainees as though uncertain of what to do. Sherlock watched it forlornly for a moment before reaching out to it. At the touch of his hand it evaporated.

"Well, that was better," John consoled. "Do you mind me asking what memory you were using?"

Sherlock smiled thinly. "My first night at Hogwarts. The moment that it sank in that I was somewhere safe, that Professor McMillian _cared_… that I could be someone different. That if I wanted to make a decision here that my parents didn't approve of, I could do it and they probably wouldn't even find out until it was too late. I remember unpacking my things in the dormitory and feeling like I could do anything." He frowned heavily. "That was better, I think, but it still didn't even have a shape."

John nodded. "That's why I asked what memory you used. It might just be that you need to practise, or concentrate more, but it might be that your happy memory wasn't strong enough. Try another one. Maybe a more recent one? Just a memory of doing something with your friends and being _content_."

But Sherlock was shaking his head. John frowned at him. "I don't… there isn't anything else. That's the happiest memory I can think of."

He caught his jaw quickly before it fell open. "_Nothing?_ You mean you haven't been…"

"I've had moments when I was happy," Sherlock reassured him, though it wasn't particularly reassuring. "But I can't use them for this because I can't think of them now without thinking of when they ended. They all ended badly and that… taints the memories."

John tried to look as though this wasn't a big deal, but it _was_. "You haven't had _one_ thing that made you happy that hasn't ended so badly it ruined the memory?"

Sherlock seemed to be avoiding John's gaze, staring uncertainly towards the corner of the room. "I know," he said. "It's unusual. I'm just weird."

"You're not _weird_, Sherlock," John said indignantly, his mind still reeling. "It's just… I…" Without allowing himself to think too much about the action, he stepped forwards and pulled the younger trainee into a tight hug. Sherlock froze, his shoulders tensing, but just as John was about to pull away and apologise he suddenly relaxed and leaned into the embrace, his arms wrapping around John's shoulderblades. John just stopped himself from shivering at the feeling of a strong, proud nose sliding down his neck as Sherlock buried his face in John's shoulder. "You're just so incredible, I can't believe people can treat you like that. You're brilliant, and you're funny, and you've helped me so much tonight, and of all the careers you could have chosen with all your brains you want to be an _Auror_ so you obviously have an amazing heart - _Merlin,_ I want to find every person who's ever pulled your happiness out from underneath you and hex them into a pulp."

The former Slytherin's breath was hot under John's collar as he huffed an incredulous chuckle. "Thank you," Sherlock said softly. "I value your opinion a lot more than theirs."

John resolved immediately to keep Sherlock as close to his chest as he could without showing him just how infatuated he was. The pure-blood deserved to have someone who told him he was fantastic every day.

For a few moments they just stood there, leaning on each other for support. Sherlock smelled of mint and bitter chocolate and just a hint of something dark and fiery; John tried to temper the desire to lick the mint away so that he could unravel the smell of Sherlock underneath. Then he wondered why he was trying. Surely there was a way he could phrase his attraction to the younger boy in a way that didn't make it sound like the be-all and end-all of their friendship. If Sherlock wasn't interested, John would happily settle for the less and the more of how they had been with one another tonight, even if he'd mistaken the barest hints of lingering looks that he'd wondered about when the gusts of laughter were fading away.

Sherlock, however, was already pulling away, looking forcibly business-like. His cheeks seemed to have taken on a permanent shade of pink that offset the rich brown of his curls in a more or less entirely endearing manner. John smiled at him. "I've got to try again," the younger boy muttered, as though apologising for ending the hug.

John took a step back; Sherlock screwed up his face in concentration. John was about to stop him and tell him he was trying too hard, but then the creases in his forehead relaxed suddenly. John watched as his friend's expression became calm, almost beatific. A tiny smile played with the edges of his mouth. Then Sherlock raised his wand and murmured, _"Expecto Patronum!_"

It burst from the end of his wand violently, as though it had been struggling for hours to get free. John's jaw fell open as it flapped past him, snapping playfully at his ear on its way, almost as long as he was tall. It was still smoky, still hazy around the edges, but it very definitely had a shape.

Sherlock's Patronus was a dragon.

John had never seen anyone cast anything but non-magical animals before. He hadn't even known it was _possible_ to have magical creatures as a Patronus. But, he supposed, letting his gaze shift from the dragon now coughing and spitting silvery flames at his sofa to its bewildered-looking owner, if anyone could, he would have guessed it to be Sherlock. He was the most magical person John had ever met. He was a blaze of intrigue and passion conducted, when he felt like it, into a beautiful and precise and _impossibly_ powerful wizard. _A dragon,_ John thought, watching Sherlock's wide green-grey eyes start to crinkle in elation. _It figures._

"Oh, _Sherlock_," John heard himself say quietly, staring at him as though to look away might cost him his eyes.

The curly-haired genius reached forward as the dragon circled the living room and headed back towards the wizard who had cast it, but before his fingers could connect with the creature it spiralled into vapour and faded, leaving stunned silence in its wake.

Sherlock cleared his throat absently, still gaping at the spot where it had vanished. "I did it," he said.

John tried to smile. "I told you you could." The former Slytherin looked back at him and beamed. "What were you thinking about? If you don't mind me asking," he added hurriedly.

"Tonight," Sherlock answered before John had even finished speaking. His impossible eyes were glowing as they scanned John's face carefully, but there was something hesitant behind them, as though he was afraid John would laugh. "This. Us. Just doing something with a friend and being content." John could feel his heartbeat pushing at the walls of his throat; he tried to swallow, but he couldn't. Sherlock was frowning, and his eyes were darting from John's eyes to his lips and back again, and as he took a hesitant, loaded step forward John couldn't move, couldn't speak, couldn't _breathe_. "John…"

And then they were kissing; Sherlock's hands were grabbing at the back of his head and his nose was pressed hard against his cheek and Sherlock was making little whimpery noises as his lips shifted against John's. It took a moment for the truth to sink in, but as soon as it had John leaped into action, securing his hands on Sherlock's hip and the small of his back so that he couldn't run away and fitting his mouth more securely around the lush swell of Sherlock's. It was enough for a moment, the pressure of lips on his and Sherlock's hot, rapid breaths blowing across his cheeks, and then suddenly it wasn't, and John had to press harder, to part his lips and tentatively add his tongue to the kiss, only to find Sherlock's lips already parted to accept it with a deep, rumbling groan.

Their tongues flirted together, teasing and promising all at the same time. John pressed his body against Sherlock's long, lean frame, a low noise escaping when his groin brushed against the neatly-tailored trousers just visible under Sherlock's robes. He wondered how the other boy could find him attractive enough to kiss with such breathless fervour, dressed as he was in Muggle jeans and a lumpy oatmeal jumper James' grandmother had knitted him at Christmas. At the touch of John's obviously aroused crotch, though, Sherlock's entire body shuddered and he began to yield to the pressure and take a few tiny half-steps backwards.

"Oh, God, you can't possibly want this," John gasped, steering Sherlock's backward shuffle towards the sofa nonetheless. "Please tell me you want this."

The teen overbalanced, his lips dislodging from where they had been sucking on John's with a disgruntled sound, and fell with a startled huff of breath onto the sofa. His hands dragged down the front of John's jumper, bunching it in his fists as he landed. "I want this," he said breathlessly. "I've wanted this for six months, don't you dare stop now."

The knowledge that they could have been doing this for six months made John dizzy. He joined Sherlock on the sofa and pulled the younger student's mouth back towards him. Sherlock made a sort of strangled whine and scrambled up until he was straddling John's lap, almost bending double in order to compensate for his height. The possibilities of this arrangement occurred to John in a dazed rush; with a groan he replaced his hands around Sherlock's hips and pulled him closer, lifting his hips to grind their groins together. The sudden and irrefutable proof that Sherlock was just as hard as he was from their snogging sucked the breath from his lungs. "I think there's some clichéd line I'm supposed to say about that," he muttered, resting his forehead against the pure-blood's.

Sherlock gusted a laugh. "Save it," he commanded, rocking his hips down again and making John gasp. "There are so many better things you could do with your mouth."

John returned the laugh, rolling his hips up to meet the not-quite-rhythmic thrusts of Sherlock's and employing his mouth in one of these better things. The younger boy was grinding down with little whimpering noises, and if John were to hazard a guess he would say that Sherlock wasn't quite aware that he was doing it. He gently gripped the curly-haired brunet's hips and guided his movements into a sustainable rhythm, brushing their lips together and then sliding his mouth down to the irresistibly flawless skin of his neck. Sherlock's moan was almost startlingly loud. "Godric," John whispered hungrily against his skin. "Look at you." He sat back for a moment, not stopping their hips rocking together, to take in the sight of Sherlock's flushed face above him. "You are Eros incarnate."

Sherlock's hands finally succeeded in the bid they had been making for sanctuary underneath John's jumper. "Eros was the god of _lust_, John," he said distractedly.

"That explains a lot," John giggled, undoing the fastenings on Sherlock's robes as gently as he could with shaking hands. Sherlock chuckled along with him, a definite shaky note to his deep voice.

They undressed each other's top halves clumsily, still rocking against each other far too lazily for John's body's liking. He wanted desperately to push the other boy down into the sofa and rut into him hard and fast – and yet, more than that, he wanted it to last. He wanted Sherlock to remember it, to not be able to think of anything or anyone _else_, to want to do it again and again and again for as long a period as possible. He slid his hands tantalisingly slowly down the flat expanse of Sherlock's belly to the hook-and-eye fastenings on his trousers and bent his head to take a dusky nipple between his teeth.

Sherlock gasped, his fingernails scraping involuntarily down John's chest as his hands convulsed into fists. "_Salazar_," he stuttered, stroking the scrapes in apology. "John… John, we've got to… your flatmate, we shouldn't do this on the sofa."

John smiled against Sherlock's pectorals. "He won't be back tonight," he reassured him. "He's staying with his girlfriend."

"That's not what I meant," Sherlock said, his voice catching as John's fingers brushed the other apparently sensitive nipple. "I don't want to get… anything… on your furniture."

Grinning at the teen's inability to use the word 'come', John stroked a tender thumb over his cheekbone. He doubted they could get anything on the sofa that wouldn't come off with a quick Scouring Charm, but the thought of having Sherlock properly horizontal on a bed was too promising to pass up. "All right," he said gently. "Bedroom, then."

He snatched his wand off the table on the way past, one hand still doggedly hanging onto one of Sherlock's belt loops, and dragged him at the fastest possible speed without breaking into a run down the hallway to his bedroom, where he proceeded to pin the younger boy against the wall and try his very hardest to slip his hand into his sinfully tight trousers, having given up the hook-and-eye as a bad job. Sherlock chuckled into his mouth and slid his own hands under the significantly looser waistband of John's jeans to grab two handfuls of his arse and pull their groins together.

"Oh, for Merlin's sake," Sherlock muttered finally, withdrawing his own hands in order to bat John's away and effortlessly unfasten his trousers, revealing tight forest-green pants. John whimpered at the sight – Sherlock's erection was straining against the fabric and there was a dark patch revealed in the vee of his open fly where the silk was wet with pre-come. The Slytherin smiled charmingly at him, his green-grey eyes sparkling with amusement.

John's mouth was so dry he couldn't speak. Sherlock's long fingers threaded through the hair at the back of his neck and pulled him close again, nosing underneath his ear. "Your turn, John," he murmured, his deep voice vibrating between John's legs. He scrambled to drop his jeans, stepping away from Sherlock to allow for the more complicated manoeuvres necessary to extricate the taller boy from his trousers. John wondered whether he had to spell himself into them in the mornings.

Sherlock stepped towards him this time, that tiny bit closer to the bed. John groaned at the feeling of Sherlock's skin against his cock through the cotton of his pants and reached automatically to get rid of the offending fabric; his hands met Sherlock's long-fingered ones at his waistband where they had apparently had the same idea, so he left them to it and started on the excessively Slytherin undergarments opposite him. _Old habits_, he supposed, remembering that his own pants were Gryfindor red.

Sherlock's skin was warm to the touch and salty to taste and absolutely _beautiful_ to look at. John stepped away from him to kick off his pants and caught his breath at the sight of the young trainee standing naked in front of him, his hands fluttering at his sides as though he was trying not to cover himself up. "God, you're gorgeous," John told him. He smiled shyly.

Gently, John steered the taller boy around with gentle kisses to his neck until he was sitting on the bed and then climbed on top of him. An unexpected brush of their naked erections made both of them moan; Sherlock fell backwards onto his elbows, his eyes closed at the sensation. John bit his lip. He knew there wasn't much chance of this lasting as long as he had wanted it to. "Move up the bed a bit, then we can lie down properly," he said quickly. His voice didn't sound like his own anymore, low and growly from arousal.

They repositioned themselves, Sherlock's cock bobbing endearingly against his stomach as he wriggled up the bed. John wanted to take it in his mouth, but Sherlock was reaching for him, pulling their mouths together, and their groins realigned so neatly that the idea went out of his head in favour of frotting against him, every inch of Sherlock's skin hot and slick against his. "Oh, God," John moaned, trying to lever himself up onto his elbows but not wanting to lose the heat of Sherlock's chest against his own. "Oh, God, where's my wand, hang on…"

Once he had retrieved his wand from where he must have dropped it somewhere along the way Sherlock kissed him shyly, his large hands running smooth trails up and down his back. "Will you fuck me?" he asked quietly, arching an earnest eyebrow.

John had to bite the inside of his cheek rather hard at the suggestion, feeling his stomach tighten and the low buzz of orgasm loom frighteningly close. He groaned helplessly, burying his face in Sherlock's shoulder. "Oh God," he repeated. "I _can't_. Sherlock, I can't, there's no way I'd get inside you without coming, I'm too close."

He brought his head up to see Sherlock's face, worried that he'd ruined it for him, that he'd be embarrassed or disappointed, but the pure-blood's elegant face curved into a smug smile. "That's... more than fine. Next time."

_Oh, God, he wants a next time_. John kissed him soundly. "I'll most definitely hold you to that," he assured him, circling his hips against Sherlock's to emphasise the point. Sherlock made a noise that seemed to stick in the back of his throat and tightened his hands on John's back, any response apparently forgotten as they sped up their movements against one another. "_Oh_, hold on, we need…"

It had been a while since John had tried to conjure lube in quite this state, and he overdid the spell a little, squirting the clear fluid across Sherlock's abdomen rather more copiously than he'd intended. The brunet chuckled. "Shut up," John growled, kissing him again. "It worked, didn't it?"

He ran his hand through the lube and then gripped both their erections together. Sherlock almost headbutted him as his body curled reflexively upwards. "_Oh,_ Salazar," he groaned, wrapping his own hand around them. John thanked all the four Founders that the younger boy seemed to be just as close as he was. Merlin knew how he had expected to last through being fucked. "Oh, tighter – _John_, yes."

"_Sherlock_," John panted, licking and sucking a patch on his shoulder. "I'm close, are you –"

Sherlock made a frantic noise. "_God_, yes, close," he agreed, speeding up his thrusts into their joined hands. John matched his rhythm, closing his eyes to better feel the hand clutching at his back and the almost-synchronised throbbing of their erections as they built towards something that promised to be utterly incredible. "Hold me, John, please, tightly," Sherlock begged, loosening the hand holding John's to their groins to let him free it. John snatched it away, feeling Sherlock tighten his grip again, even tighter than before, and slipped both hands under the younger boy's back instead to hold him close, so tightly he must have struggled to breathe, but Sherlock only gasped a desperate _yes_ before he was coming with a long, wordless shout, his body twisting and flailing in John's arms and hot fluid spilling over his fingers between their bellies. John grunted his name as he followed, the climax so blinding that for the longest of moments he couldn't see, couldn't feel anything but pleasure and Sherlock's hands, one stroking him firmly through the climax, the other holding around his back to keep him still and safe.

When it was finally over his limbs collapsed; it was lucky he was already leaning half of his weight on Sherlock and the other half on the bed, or he might have squashed the Slytherin. Panting, Sherlock wiped his hand up the skin of his own thigh and wrapped it around John's back, pressing a kiss to his forehead. John sighed happily and burrowed closer to him, his eyes falling closed.

"John," Sherlock murmured, sounding as sleepy as John felt. He lifted his head and hummed inquisitively. "Is this… what do you… _want_ from this? From me?"

John propped himself tiredly onto one elbow in order to direct a more serious look at him. "I want everything you want to give me," he replied fervently. "For as long as you want to give it to me."

Sherlock smiled the same shy smile John had seen every time he was paid a compliment. "Careful, you'll be stuck with everything I have, forever," he said quietly. It sounded like a joke, but John could see the fear of rejection behind his green-grey eyes; he reached out and stroked the boy's cheekbone tenderly.

"I was hoping you'd say that," he said, grinning. Sherlock's face split into a disbelieving grin. John laughed delightedly and tucked himself back against him. "You're the most incredible person I've ever met," he reassured the other boy, "and I've spent a fair bit of time with Harry Potter."

* * *

John breezed through the written exam the next morning, smiling at his memories of the charms and spells his new lover had used to help him remember the facts he was regurgitating and sneaking occasional glances at the desk where Sherlock was sitting to help boost the recall. The glances he stopped around three-quarters of the way through the exam when he looked up to find that Sherlock had rolled up his own parchment, evidently finished, and was now chewing on the end of his quill and staring at him in a way that left absolutely no doubt in his head as to what he was thinking about. John flushed and didn't look at Sherlock again until he'd rolled up his own paper and felt free to return the suggestive expression in full force.

Sherlock seemed to come to himself at the feeling of John's eyes on him; he flushed a heavy red but didn't look away, lowering his eyelashes for a heartbeat before returning the sensual stare with an intensity that John wasn't sure would be _possible_ with eyes other than Sherlock's. John licked his lips, making the sentiment as clear as he could. When this was over and they were home – John's or Sherlock's, he didn't care – he was going to take the other boy apart with those lips, with that tongue. Sherlock's blush darkened, and his own full cupid's bow twitched into a luxurious smile.

The practical part of the exam followed startlingly like John remembered his Defence Against the Dark Arts OWL, with all the first-year Auror trainees sitting nervously outside the training-room in the bowels of the Ministry and waiting for their name to be called so that one of the senior Aurors could check that they could perform the spells they'd been taught in this particular portion of their training.

Sherlock's name was called first, which made perfect alphabetical sense. He turned a nervous glance down at John, sitting cross-legged on the floor beside him. John wanted to kiss him, but they hadn't said anything about showing the rest of the trainees what was between them, so he smiled reassuringly back at him instead. "You'll be fine," he said softly. "Just remember what I told you last night."

The younger trainee grinned brilliantly. "Which bit?" he asked. John hit the highest bit of him he could reach, which in this position turned out to be his lower thigh.

When, ten minutes later, an exultant roar sounded from the exam room – one that John had heard in his living room the night before, one that could only possibly have come from a dragon – he grinned triumphantly to himself and listened in silence to the awed speculation from his classmates.

He was still buzzing when his own name was called, and consequently his own Patronus glowed so brightly the examiner actually clapped.

"Brilliant, Mr Watson," she said, sounding slightly breathless. "That's one of the strongest I've seen today."

John smiled warmly at her and confided his secret. "I had an _excellent_ study partner."


End file.
